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	<title>three.js webgl - post processing - pixelation</title>
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	<div id="info">
		<a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> - Pixelation pass with optional single pixel outlines by
		<a href="https://github.com/KodyJKing" target="_blank" rel="noopener">Kody King</a><br /><br />
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	<!-- Import maps polyfill -->
	<!-- Remove this when import maps will be widely supported -->
	<script async src="https://unpkg.com/es-module-shims@1.3.6/dist/es-module-shims.js"></script>

	<script type="importmap">
		{
			"imports": {
				"three": "../build/three.module.js",
				"three/addons/": "./jsm/"
			}
		}
	</script>

	<script type="module">

		import * as THREE from 'three';

		import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
		import { EffectComposer } from 'three/addons/postprocessing/EffectComposer.js';
		import { RenderPixelatedPass } from 'three/addons/postprocessing/RenderPixelatedPass.js';
		import { GUI } from 'three/addons/libs/lil-gui.module.min.js';

		let camera, scene, renderer, composer, crystalMesh, clock;
		let gui, params;

		init();
		animate();

		function init() {

			const aspectRatio = window.innerWidth / window.innerHeight;

			camera = new THREE.OrthographicCamera( - aspectRatio, aspectRatio, 1, - 1, 0.1, 10 );
			camera.position.y = 2 * Math.tan( Math.PI / 6 );
			camera.position.z = 2;

			scene = new THREE.Scene();
			scene.background = new THREE.Color( 0x151729 );

			clock = new THREE.Clock();

			renderer = new THREE.WebGLRenderer();
			renderer.shadowMap.enabled = true;
			//renderer.setPixelRatio( window.devicePixelRatio );
			renderer.setSize( window.innerWidth, window.innerHeight );
			document.body.appendChild( renderer.domElement );

			composer = new EffectComposer( renderer );
			const renderPixelatedPass = new RenderPixelatedPass( 6, scene, camera );
			composer.addPass( renderPixelatedPass );

			window.addEventListener( 'resize', onWindowResize );

			const controls = new OrbitControls( camera, renderer.domElement );
			controls.maxZoom = 2;

			// gui

			gui = new GUI();
			params = { pixelSize: 6, normalEdgeStrength: .3, depthEdgeStrength: .4, pixelAlignedPanning: true };
			gui.add( params, 'pixelSize' ).min( 1 ).max( 16 ).step( 1 )
				.onChange( () => {

					renderPixelatedPass.setPixelSize( params.pixelSize );
		
				} );
			gui.add( renderPixelatedPass, 'normalEdgeStrength' ).min( 0 ).max( 2 ).step( .05 );
			gui.add( renderPixelatedPass, 'depthEdgeStrength' ).min( 0 ).max( 1 ).step( .05 );
			gui.add( params, 'pixelAlignedPanning' );

			// textures

			const loader = new THREE.TextureLoader();
			const texChecker = pixelTexture( loader.load( 'textures/checker.png' ) );
			const texChecker2 = pixelTexture( loader.load( 'textures/checker.png' ) );
			texChecker.repeat.set( 3, 3 );
			texChecker2.repeat.set( 1.5, 1.5 );

			// meshes

			const boxMaterial = new THREE.MeshPhongMaterial( { map: texChecker2 } );
		
			function addBox( boxSideLength, x, z, rotation ) {

				const mesh = new THREE.Mesh( new THREE.BoxGeometry( boxSideLength, boxSideLength, boxSideLength ), boxMaterial );
				mesh.castShadow = true;
				mesh.receiveShadow = true;
				mesh.rotation.y = rotation;
				mesh.position.y = boxSideLength / 2;
				mesh.position.set( x, boxSideLength / 2 + .0001, z );
				scene.add( mesh );
				return mesh;
		
			}

			addBox( .4, 0, 0, Math.PI / 4 );
			addBox( .5, - .5, - .5, Math.PI / 4 );

			const planeSideLength = 2;
			const planeMesh = new THREE.Mesh(
				new THREE.PlaneGeometry( planeSideLength, planeSideLength ),
				new THREE.MeshPhongMaterial( { map: texChecker } )
			);
			planeMesh.receiveShadow = true;
			planeMesh.rotation.x = - Math.PI / 2;
			scene.add( planeMesh );

			const radius = .2;
			const geometry = new THREE.IcosahedronGeometry( radius );
			crystalMesh = new THREE.Mesh(
				geometry,
				new THREE.MeshPhongMaterial( {
					color: 0x2379cf,
					emissive: 0x143542,
					shininess: 10,
					specular: 0xffffff
				} )
			);
			crystalMesh.receiveShadow = true;
			crystalMesh.castShadow = true;
			scene.add( crystalMesh );

			// lights

			scene.add( new THREE.AmbientLight( 0x2d3645, 1.5 ) );

			const directionalLight = new THREE.DirectionalLight( 0xfffc9c, .5 );
			directionalLight.position.set( 100, 100, 100 );
			directionalLight.castShadow = true;
			directionalLight.shadow.mapSize.set( 2048, 2048 );
			scene.add( directionalLight );

			const spotLight = new THREE.SpotLight( 0xff8800, 1, 10, Math.PI / 16, .02, 2 );
			spotLight.position.set( 2, 2, 0 );
			const target = spotLight.target;
			scene.add( target );
			target.position.set( 0, 0, 0 );
			spotLight.castShadow = true;
			scene.add( spotLight );

		}

		function onWindowResize() {

			const aspectRatio = window.innerWidth / window.innerHeight;
			camera.left = - aspectRatio;
			camera.right = aspectRatio;
			camera.updateProjectionMatrix();

			renderer.setSize( window.innerWidth, window.innerHeight );
			composer.setSize( window.innerWidth, window.innerHeight );

		}

		function animate() {

			requestAnimationFrame( animate );

			const t = clock.getElapsedTime();
		
			crystalMesh.material.emissiveIntensity = Math.sin( t * 3 ) * .5 + .5;
			crystalMesh.position.y = .7 + Math.sin( t * 2 ) * .05;
			crystalMesh.rotation.y = stopGoEased( t, 2, 4 ) * 2 * Math.PI;

			const rendererSize = renderer.getSize( new THREE.Vector2() );
			const aspectRatio = rendererSize.x / rendererSize.y;
			if ( params[ 'pixelAlignedPanning' ] ) {

				pixelAlignFrustum( camera, aspectRatio, Math.floor( rendererSize.x / params[ 'pixelSize' ] ),
					Math.floor( rendererSize.y / params[ 'pixelSize' ] ) );

			} else if ( camera.left != - aspectRatio || camera.top != 1.0 ) {

				// Reset the Camera Frustum if it has been modified
				camera.left = - aspectRatio;
				camera.right = aspectRatio;
				camera.top = 1.0;
				camera.bottom = - 1.0;
				camera.updateProjectionMatrix();

			}

			composer.render();

		}

		// Helper functions

		function pixelTexture( texture ) {

			texture.minFilter = THREE.NearestFilter;
			texture.magFilter = THREE.NearestFilter;
			texture.generateMipmaps = false;
			texture.wrapS = THREE.RepeatWrapping;
			texture.wrapT = THREE.RepeatWrapping;
			return texture;

		}

		function easeInOutCubic( x ) {

			return x ** 2 * 3 - x ** 3 * 2;

		}

		function linearStep( x, edge0, edge1 ) {

			const w = edge1 - edge0;
			const m = 1 / w;
			const y0 = - m * edge0;
			return THREE.MathUtils.clamp( y0 + m * x, 0, 1 );

		}

		function stopGoEased( x, downtime, period ) {

			const cycle = ( x / period ) | 0;
			const tween = x - cycle * period;
			const linStep = easeInOutCubic( linearStep( tween, downtime, period ) );
			return cycle + linStep;

		}

		function pixelAlignFrustum( camera, aspectRatio, pixelsPerScreenWidth, pixelsPerScreenHeight ) {

			// 0. Get Pixel Grid Units
			const worldScreenWidth = ( ( camera.right - camera.left ) / camera.zoom );
			const worldScreenHeight = ( ( camera.top - camera.bottom ) / camera.zoom );
			const pixelWidth = worldScreenWidth / pixelsPerScreenWidth;
			const pixelHeight = worldScreenHeight / pixelsPerScreenHeight;

			// 1. Project the current camera position along its local rotation bases
			const camPos = new THREE.Vector3(); camera.getWorldPosition( camPos );
			const camRot = new THREE.Quaternion(); camera.getWorldQuaternion( camRot );
			const camRight = new THREE.Vector3( 1.0, 0.0, 0.0 ).applyQuaternion( camRot );
			const camUp = new THREE.Vector3( 0.0, 1.0, 0.0 ).applyQuaternion( camRot );
			const camPosRight = camPos.dot( camRight );
			const camPosUp = camPos.dot( camUp );

			// 2. Find how far along its position is along these bases in pixel units
			const camPosRightPx = camPosRight / pixelWidth;
			const camPosUpPx = camPosUp / pixelHeight;

			// 3. Find the fractional pixel units and convert to world units
			const fractX = camPosRightPx - Math.round( camPosRightPx );
			const fractY = camPosUpPx - Math.round( camPosUpPx );

			// 4. Add fractional world units to the left/right top/bottom to align with the pixel grid
			camera.left = - aspectRatio - ( fractX * pixelWidth );
			camera.right = aspectRatio - ( fractX * pixelWidth );
			camera.top = 1.0 - ( fractY * pixelHeight );
			camera.bottom = - 1.0 - ( fractY * pixelHeight );
			camera.updateProjectionMatrix();

		}
		
	</script>
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